Reactive choke for automatic wellbore fluid management and methods of using same

ABSTRACT

Fluid actuated chokes comprise an expandable material that expands due to an undesired fluid coming in contact with the choke. The choke includes one or more passageways through which desired fluids from a well flow unimpeded. The choke is disposed in a downhole tool as part of a downhole completion. When one or more undesired fluids enters a production stream flowing through the downhole completion and, thus, the downhole tool, and contacts the choke, the expandable material expands causing fluid flow through the passageway(s) to be restricted and, in some cases, completely closed off. Thus, the choke automatically detects and reacts, i.e., restricts fluid flow through the choke, when contacted by the undesired fluid(s).

BACKGROUND

1. Field of Invention

The present invention is directed to chokes for use in downhole tools,and in particular, to reactive, fluid actuated, chokes disposed indownhole tools that enable automatic prevention of undesired fluids fromentering or exiting a production stream in downhole completions byexpanding upon exposure to one or more undesired fluids causingrestriction of fluid flow through the choke and, thus, the downholetools.

2. Description of Art

During production of fluids from a well, one or more fluid flows fromthe formation of the well into a downhole completion. This flowing offluid is referred to as a production stream. The terms “fluid” and“fluids” as used herein can include oil, gas, water, brine, and thelike. Generally, it is desired to produce only hydrocarbons from a welland leave all other fluids within the well. However, in some instances,it may be desirable to remove well or brine from the well and leave thehydrocarbons for later production. In either situation, at least onefluid is desired to be produced, i.e., flowed from the formation, intothe downhole completion and out of the well, while other fluids areundesired.

SUMMARY OF INVENTION

Broadly, the fluid actuated chokes in downhole tools disclosed hereininclude an expandable body comprising one or more passageways disposedtherein. Desired fluid(s) are permitted to flow through thepassageway(s) unimpeded as part of the production stream. Undesiredfluid(s) are restricted from flowing through the passageways due toexpansion of the expandable body. The expandable body expands whencontacted with the undesirable fluid(s). As a result, the passageway(s)move from an initial position which provides a initial flow rate throughthe passageway(s) towards an expanded or restricted position thatprovides a second, lesser, flow rate through the passageway(s).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of one specific embodiment of adownhole tool having one specific embodiment of the fluid actuatedchokes disclosed herein.

FIG. 2 is a perspective view of one specific embodiment of the fluidactuated chokes disclosed herein.

FIG. 3A is a partial cross-sectional view of the reactive choke of FIG.2 taken along line 2-2 showing the fluid actuated choke in its initialposition.

FIG. 3B is a partial cross-sectional view of the reactive choke of FIG.2 taken along line 2-2 showing fluid actuated choke in one of itsplurality of restricted or expanded positions.

FIG. 4 is a partial cross-sectional view of another specific embodimentof the fluid actuated chokes disclosed herein showing the fluid actuatedchoke in its initial position.

FIG. 5 is a partial cross-sectional view of an additional specificembodiment of the fluid actuated chokes disclosed herein showing thefluid actuated choke in its initial position.

FIG. 6 is a partial cross-sectional view of another specific embodimentof the fluid actuated chokes disclosed herein showing the fluid actuatedchoke in its initial position.

FIG. 7 is a partial cross-sectional view of an additional specificembodiment of the fluid actuated chokes disclosed herein showing thefluid actuated choke in its initial position.

FIG. 8 is a cross-sectional view of another embodiment of a downholetool having one specific embodiment of the fluid actuated chokesdisclosed herein.

FIG. 9 is a partial cross-sectional view of the downhole tool of FIG. 8showing the fluid actuated choke in its initial position.

While the invention will be described in connection with the preferredembodiments, it will be understood that it is not intended to limit theinvention to these embodiments. On the contrary, it is intended to coverall alternatives, modifications, and equivalents, as may be includedwithin the spirit and scope of the invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF INVENTION

Referring now to FIGS. 1-3B, downhole tool 20 comprises tubular member21, having outer wall surface 22 and inner wall surface 23 defining bore24. Choke 30 is disposed within bore 24 thereby dividing bore 24 intoupper bore portion 25 and lower bore portion 26. As discussed in greaterdetail below, a fluid, such as oil, gas, brine, water and the like,initially flow through choke 30 either in an upward direction or adownward direction. In other words, the fluid initially flows from lowerbore portion 26, through choke 30, and into upper bore portion 25, orfrom upper bore portion 25, through choke 30, and into lower boreportion 26.

As best illustrated in FIG. 2, choke 30 comprises body 31, having uppersurface 32, lower surface 33, side surface 34, and a plurality ofpassageways 35 disposed between upper and lower surfaces 32, 33 therebypermitting a fluid to flow through body 31. As shown in the FIG. 2, body31 has one side surface 34 because body is cylindrically, or disc,shaped. In other embodiments, body 31 may have another shape, e.g., apolygonal shape such as a square shape, a rectangular shape, hexagonalshape or the like (not shown). In such embodiments, body 31 would behave more than one side surface 34.

Body 31 is formed, at least in part, by an expandable material that iscapable of expanding to restrict fluid flow through passageway(s) 35 dueto contact with an undesired fluid, e.g., hydrocarbon, brine, water, andthe like. Referring to FIGS. 3A and 3B, when contacted by the undesiredfluid, body 31 expands such that body 31 and, thus, expandable materialand passageway 35, moves from the initial configuration or position(FIG. 3A) to the restricted or expanded configuration or position (FIG.3B) in which the flow of the undesired fluid through passageway 35 islessened. In other words, the flow rate of fluid through passageway 35is decreased. As shown in FIG. 3B, passageway 35 is not completelyclosed off due to the expansion of expandable material of body 31 fromthe initial configuration. It is to be understood, however, that inother embodiments, passageway 35 is completely closed off such that theflow rate of fluid through passageway 35 is substantially zero, i.e.,less than 5% of the original flow capacity permitted to flow throughpassageway 35 when the expandable material is in the initialconfiguration.

In one specific embodiment, body 31 is formed completely out of theexpandable material. In other embodiments, body 31 includesnon-expandable components such as stiffing rings or other supportstructures or substrates to which the expandable material is connected.Further, in one embodiment, the expandable materials expand by absorbingthe undesired fluid.

Suitable expandable materials include urethane and polyurethanematerials, including polyurethane foams, biopolymers, and superabsorbentpolymers. Nitriles and polymers sold as 1064 EPDM from RubberEngineering in Salt Lake City, Utah are acceptable expandable materials.In one embodiment, the expandable material comprises a swellable polymersuch as cross-linked or partially cross-linked polyacrylamide,polyurethane, ethylene propylene, or other material capable of absorbinghydrocarbon or aqueous, or other fluids, and, thus, swelling to restrictpassageway(s) 35. Additional suitable expandable materials includeelastomers such as nitrile rubber (“NBR”), hydrogenated nitrile rubber(“HNBR”), carboxyl nitrile rubber (“XNBR”), silicone rubber,ethylene-propylene-diene copolymer (“EPDM”), fluoroelastomer (“FKM,”“FEPM”) and perfluoroelastomer (“FFKM”); and cross-linked polymers suchas water-soluble methylcellulose, cellulose acetate phtalate, andhydroxypropyl methylcellulose polymers, poly (ethylene oxide) polymers,guar and its derivatives, polyacrylamide, silicon-based materials, andflouro-silicone based materials. Still other expandable materials aredisclosed in U.S. Pat. No. 7,091,771 B2 which is hereby incorporated byreference herein in its entirety.

In another embodiment, the expandable material is a shape-memorymaterial, for example, a compressed elastomer or polymer that is held inthe compressed state by a dissolvable material. In one such embodiment,the expandable materials or body 31 itself, including the surface areaof body 31 within passageway(s) 35 may be encapsulated with a layer ofmaterial dissolvable by fluids such as water, brine, hydraulic fluid,hydrocarbons, and the like. As used herein, the term “encapsulated” and“encapsulating” means that the dissolvable material forms an initialbarrier between the fluid and the expandable materials or body 31. Insuch embodiments, the encapsulated layer allows the use of expandablematerials, and body 31 formed from expandable material(s), that expandvirtually instantaneously upon contacting the fluid by protecting theexpandable material(s) until expansion is desired.

Encapsulating dissolvable materials for encapsulating the expandablematerials may be any material known to persons of ordinary skill in theart that can be dissolved, degraded, or disintegrated over an amount oftime by a temperature or fluid such as water-based drilling fluids,hydrocarbon-based drilling fluids, or natural gas. Preferably, theencapsulating dissolvable material is calibrated such that the amount oftime necessary for the dissolvable material to dissolve is known oreasily determinable without undue experimentation. Suitableencapsulating dissolvable materials include polymers and biodegradablepolymers, for example, polyvinyl-alcohol based polymers such as thepolymer HYDROCENE™ available from Idroplax, S.r.l. located inAltopascia, Italy, polylactide (“PLA”) polymer 4060D from Nature-Works™,a division of Cargill Dow LLC; TLF-6267 polyglycolic acid (“PGA”) fromDuPont Specialty Chemicals; polycaprolactams and mixtures of PLA andPGA; solid acids, such as sulfamic acid, trichloroacetic acid, andcitric acid, held together with a wax or other suitable binder material;polyethylene homopolymers and paraffin waxes; polyalkylene oxides, suchas polyethylene oxides, and polyalkylene glycols, such as polyethyleneglycols. These polymers may be preferred where water is the undesiredfluid because they are slowly soluble in water.

As shown in FIG. 1, choke 30 is encircled by rigid tubular member 70which can facilitate securing choke 30 within bore 24. Tubular member 70provides resistance to outward expansion of body 31 and, thus,facilitates restriction of passageway(s) 35 during expansion of body 31.In the embodiment of FIG. 1, tubular member 70 also comprises a topretainer 71 disposed on upper surface 32 and a bottom retainer 72disposed on lower surface 33 to provide resistance to upward anddownward expansion of body 31. Thus, upper and lower retainers 71, 72further facilitate restriction of passageway(s) 35. In anotherembodiment (not shown), upper and lower retainers 71, 72 extend over theentire upper and lower surfaces 32, 33 and include holes that are in atleast partial alignment with each passageway 35. In this embodiment,upper and lower retainers 71, 72 provide addition resistance to upwardand downward expansion by body 31 so that each passageway 35 can berestricted; yet fluid can flow through upper and lower retainers 71, 72prior to expansion of body 31 due to the holes being at least partiallyaligned with corresponding passageways 35.

As shown in the embodiment of FIGS. 1-3B, choke 30 comprises a pluralityof passageways 35 having a cylindrical cross-sectional shape such thatthe intersection of each passageway 35 with upper and lower surfaces 32,33 provides a substantially circular shape, each circular shape having asubstantially identical circumference. In other embodiments, such as theembodiment shown in FIG. 4, one or more passageways 35 comprises aserrated cross-sectional shape. As shown in FIG. 4, one side of thecross-sectional shape of passageway 35 has serrations that arereciprocal in shape to the serrations on the opposite side of thecross-sectional shape of passageway 35. Thus, upon expansion of body 31,the serrations of one side fit into the reciprocally-shaped serrationsof the opposite side to facilitate restriction of fluid flow throughpassageway(s) 35.

In still other embodiments, one or more of passageways 35 may have aconically-shaped cross-section (FIG. 5) in which the intersection ofpassageway 35 with the upper surface 32 provides a circular shape havinga circumference that is smaller than a circular shape of theintersection of passageway 35 with the lower surface. Alternatively, thecircumference of the circular shape of the intersection of passageway 35with lower surface 33 may be smaller than the circumference of thecircular shape of the intersection of passageway 35 with the uppersurface.

In another embodiment shown in FIG. 6, one or more passageways 35comprises a curved cross-section, wherein one side has a convex shapeand an opposite side has reciprocally shaped concave shape so that, uponexpansion of body 31, the convex shaped side fits into the concave shapeside to facilitate restriction of the flow of fluid throughpassageway(s) 35.

In yet another embodiment shown in FIG. 7, the sides of thecross-sectional shape of one or more passageways 35 have a singlechevron cross-sectional shape in which one side fits into a reciprocallyshaped chevron shape on an opposite side of the cross-sectional shape ofpassageway 35 to facilitate restriction of fluid flow throughpassageway(s) 35.

Referring now to FIGS. 8-9, in another embodiment, downhole tool 80comprises tubular member 81 having outer wall surface 82 and inner wallsurface 83 defining bore 84. Choke 30, upper porous media 50, and lowerporous media 60, are disposed within bore 84 thereby dividing bore 84into upper bore portion 85 and lower bore portion 86. Choke 30 can beany of the embodiments disclosed and taught herein. Upper and lowerporous media 50, 60 can be any porous media known in the art thatpermits fluid to flow through them. Suitable porous media include Teflonfoam or metal screen.

A fluid, such as oil, gas, brine, water and the like, initially flowsthrough choke 30, upper media 50, and lower media 60 in either in anupward direction or a downward direction. In other words, the fluidinitially flows from lower bore portion 86, through lower media 60,choke 30, and upper media 50 into upper bore portion 85, or from upperbore portion 85, through upper media 50, choke 30, and lower media 60into lower bore portion 86.

As best illustrated in FIG. 9, choke 30, upper media 50, and lower media60 are engaged to inner wall surface 83 of tubular member 85 andretained in place by upper and lower retainers 87, 89. Thus, tubularmember 85 provides resistance to outward expansion of body 31 and, thus,facilitates inward expansion of body 31, thereby causing passageway(s)35 to be restricted. Upper media 50 is engaged with upper surface 32 ofbody 31 and lower media 60 is engaged with lower surface 33. Thus, upperand lower media 50, 60 provide resistance to upward and downwardexpansion, respectively, of body 31 and, accordingly, facilitatesrestriction of passageway(s) 35 during expansion of body 31. Inaddition, upper and lower retainers 87, 89 provide additional resistanceto upward and lower expansion, respectively, by body 31 to furtherfacilitate restriction of passageway(s) 35.

In yet another embodiment, not shown in the Figures, the choke includesan opening through which a mandrel, pipe, or other tubular member ispassed. In this embodiment, the choke is disposed on an outer diameterof the mandrel, pipe or other tubular member so that the fluid flowsthrough the passageways disposed outside of the mandrel, pipe, or othertubular member. In one particular embodiment of this arrangement, thechoke is static and disposed on the outer diameter of the mandrel, pipe,or other tubular member. In another particular embodiment of thisarrangement, the choke is disposed on a sliding sleeve that is insliding engagement with the outer diameter of the mandrel, pipe or othertubular member.

In operation, a downhole tool is disposed within a downhole completionat a desired location. Fluid is then permitted to flow from theformation as part of a production stream flowing through the downholecompletion and, thus, through the downhole tool. Disposed within aproduction stream flow path through the downhole tool is a fluidactivated choke such as those disclosed herein. Desired fluids arepermitted to flow through the choke unimpeded. However, if an undesiredfluid contacts the choke, the choke automatically restricts fluid flowthrough the choke due to the expansion of one or more expandablematerials forming the body of the choke.

Depending on the fluid that is desired to be removed from the well, thedesired fluid that is permitted to flow unimpeded through the choke canbe hydrocarbons, brine, water, and the like. Similarly, the undesiredfluid can also be hydrocarbons, brine, water, and the like. In otherwords, in some operations, it may be desirable to remove water from thewell and leave hydrocarbons within the well for future production. Inthese operations, the choke will permit water to flow through thedownhole completion unimpeded, but will automatically restrict the flowof hydrocarbons through the choke when the choke is contacted with thehydrocarbons. Conversely, in other operations it may be desirable toremove hydrocarbons from the well and leave water within the well. Inthese operations, the choke will permit hydrocarbons to flow through thedownhole completion unimpeded, but will automatically restrict the flowof water through the choke when the choke is contacted with the water.

In certain particular embodiments of the operation of the chokesdisclosed herein, the choke is reversible. That is, the choke can beclosed off or restricted by contact with the undesired fluid; however,after the undesired fluid is not longer in contact with the choke, orthe choke is placed in contact with a desired fluid, the passageway(s)through the choke move toward their original open or unrestrictedposition and, in some embodiments, the passageway(s) return all the wayto their original open or unrestricted position. Thus, the desired fluidis again permitted to flow through the choke. Afterwards, the choke canagain be activated by an undesired fluid to restrict fluid flow throughthe choke. Later, the choke can be reopened and the process ofrestricting fluid flow through the passageways, and then reopening thepassageways, can be repeated.

In one experiment, a choke was formed comprising water swellable rubberhaving a blend of NBR and polyacrylamide sold under the designationDPNT04 0207 available from BASF located in Florham Park, N.J. The chokecomprised a disc-shape having a continuous thickness of 0.085 inches anda diameter of 0.950 inches. Forty-three circular holes or passagewayseach having a diameter of approximately 0.620 inches were disposedthrough the body of the choke. The choke was placed between an upper andlower porous media each comprising Teflon foam. The upper porous mediahad a disc-shape with a diameter of 0.950 inches and a thickness of1.000 inch. The lower porous media had a disc-shape with a diameter of0.950 inches and a thickness of 1.500 inches.

The upper porous media, choke, and lower porous media were placed in a 1inch diameter flow loop with the direction of fluid flow passing throughthe lower porous media, then through the choke, and then through theupper porous media. Initially, oil (LVT 200) was flowed through the flowloop at 180° F. at a rate of 100 ml/min. Pressure readings, in pressureper square inch, were taken each minute for 20 seconds. The pressureremained steady at approximately 0.5 psi for the first 75 minutes of theexperiment. At the 75th minute of the experiment, the oil was replacedwith a solution of 30% brine water (solution of 30% salt in water).Pressure readings were again taken each minute for 20 seconds over a 75minute interval, starting at the 88th minute of the experiment. Inaddition, after 30 minutes, the percentage of brine cut was increaseduntil the brine water reached 100%. During the 75 minute interval inwhich brine water was flowed through the flow loop, the pressure of thefluid flowing through the flow loop increased from approximately 1.0 psiat 30% brine water to approximately 2.9 psi at 100% brine water. At the163rd minute of the experiment, the 100% brine water was replaced withoil (LVT 200). Thereafter, from the 163rd minute through the 295thminute of the experiment pressure readings of the oil flowing throughthe flow loop were taken each minute for 20 seconds. The pressure of thefluid decreased from approximately 2.2 psi at the 165th (100% oil)minute of the experiment to approximately 0.9 psi at the 295th minute ofthe experiment.

As illustrated by the this experiment, the desired fluid, oil, ispermitted to flow through the choke at a relatively low pressure;however, upon being contacted by brine water (the undesired fluid), thechoke swells and the passageways are closed off causing an increase inpressure within the flow loop. Removal of the brine water reverses theswelling of the choke resulting in the passageways be reopened to permitoil to flow through. Thus, the choke is reversible and repeatable suchthat fluid flow through the choke can be decreased and then increased.

It is to be understood that the invention is not limited to the exactdetails of construction, operation, exact materials, or embodimentsshown and described, as modifications and equivalents will be apparentto one skilled in the art. For example, the passageways through thechoke can have any desired or necessary cross-sectional shape tofacilitate restriction of fluid flow through the choke. Further, not allof the passageways in the choke are required to have the samecross-sectional shape. Moreover, the choke can have as few as a singlepassageway or a plurality of passageways. Additionally, it is notrequired that all fluid flow be prevented from flowing through the chokeafter expansion of the expandable material. To the contrary, some fluidmay be allowed to continue to flow through the choke which can stillindicate to the operator of the well such as by pressure changes or flowrate changes that an undesired fluid has entered the production streamso that the operator can make desired adjustments to the production ofthe well. In addition, it is to be understood that when one of theexpandable material, the body, or the passageway is in a first or aninitial configuration or position, the remainder of these components isalso in the first or initial configuration or position. Likewise, one ofthe expandable material, the body, or the passageway is in a secondconfiguration or position, the remainder of these components is also inthe second configuration or position. Further, the tubular members arenot required to have a circular cross-section. Instead, the tubularmember can have a polygonal shape or any other shape desired ornecessary to flow a production stream through the tubular member.Moreover, the choke is not required to be cylindrically or disc shaped,but can have any other shape desired or necessary to sufficientlyrestrict fluid flow through the downhole tool when contacted by one ormore undesired fluids. Further, in embodiments in which the choke isreversible, the passageway(s) are not required to return to theiroriginal positions. All that is required is that the passageway(s) movetoward their original positions such that increased fluid flow ispermitted through the passageway(s). Accordingly, the invention istherefore to be limited only by the scope of the appended claims.

What is claimed is:
 1. A downhole tool through which a production streamflows, the downhole tool comprising: a fluid actuated choke, the fluidactivated choke comprising a body having an upper surface, a lowersurface and, a passageway connecting the upper surface with the lowersurface, the body being comprised of an expandable material having afirst configuration in which fluid flows through the passageway at afirst flow rate and a second configuration in which fluid flows thepassageway at a second flow rate, the first flow rate being greater thanthe second flow rate, wherein the expandable material expands from thefirst configuration to the second configuration due to a first fluidcontacting the expandable material.
 2. The downhole tool of claim 1,wherein the first fluid causing expansion of the expandable materialfrom the first configuration to the second configuration is water. 3.The downhole tool of claim 1, wherein the first fluid causing expansionof the expandable material from the first configuration to the secondconfiguration is a hydrocarbon.
 4. The downhole tool of claim 1, whereinthe second flow rate is zero.
 5. The downhole tool of claim 1, whereinthe body is disposed in a rigid tubular member to facilitate movement ofthe expandable material from the first configuration to the secondconfiguration.
 6. The downhole tool of claim 1, wherein the bodycomprises a plurality of passageways, each of the plurality ofpassageways having a first configuration associated with a first flowrate and a second configuration associated with a second flow rate, eachof the first flow rates being greater than each of the respective secondflow rates.
 7. The downhole tool of claim 1, wherein the passageway hasa substantially cylindrical cross-sectional shape.
 8. The downhole toolof claim 1, wherein the passageway intersects the upper surface at afirst intersection, the first intersection having a first substantiallycircular shape.
 9. The downhole tool of claim 8, wherein the passagewayintersects the lower surface at a second intersection, the secondintersection having a second substantially circular shape.
 10. Thedownhole tool of claim 9, wherein the first substantially circular shapecomprises a first circumference and the second substantially circularshape comprises a second circumference, the first circumference beinggreater than the second circumference.
 11. The downhole tool of claim 1,wherein the expandable material comprises a swellable polymer.
 12. Thedownhole tool of claim 1, wherein the expandable material comprises anencapsulating dissolvable material encapsulating the expandable materialto prevent expansion of the expandable material from the firstconfiguration to the second configuration until the encapsulatingdissolvable material is dissolved by the first fluid.
 13. The downholetool of claim 1, wherein the expandable material is reversible such thatthe expandable material moves from the second configuration toward thefirst configuration when contacted by a second fluid.
 14. The downholetool of claim 1, wherein the upper surface of the body is in contactwith a first rigid porous media.
 15. The downhole tool of claim 14,wherein, wherein the lower surface of the body is in contact with asecond rigid porous media.
 16. A method of restricting fluid flowthrough a downhole tool, the method comprising the steps of: (a) flowingfluid through a fluid flow path of a downhole tool, the downhole toolhaving disposed within the fluid flow path a fluid actuated choke, thefluid actuated choke comprising a body having an upper surface, a lowersurface and, a passageway connecting the upper surface with the lowersurface, the body being comprised of an expandable material having afirst configuration in which fluid flows through the passageway at afirst flow rate and a second configuration in which fluid flows thepassageway at a second flow rate, the first flow rate being greater thanthe second flow rate; and (b) contacting the expandable material of thefluid actuated choke with a first fluid causing the expandable materialto expand from the first configuration toward the second configurationcausing the passageway to move from an initial position toward a closedposition, thereby restricting the fluid flowing through the passagewayfrom the first flow rate to the second flow rate.
 17. The method ofclaim 16, wherein the during step (b) the first fluid dissolves adissolvable material encapsulating the expandable material.
 18. Themethod of claim 16, wherein during step (a), the fluid flows at thefirst flow rate through a first porous media, then through thepassageway, and then through a second porous media.
 19. The method ofclaim 16, wherein the second flow rate is substantially zero.
 20. Themethod of claim 16, further comprising the step of: (c) contacting theexpandable material of the fluid actuated choke with a second fluidcausing the expandable material to move from the second configurationtoward the first configuration causing the passageway to move toward theinitial position, thereby increasing fluid flow through the passageway.21. The method of claim 20, wherein step (b) is repeated.